Question: $\left(-9x - 6\right)\left(9x + 1\right) = \ ?$
$= -9x \cdot \left(9x + 1\right) - 6 \cdot \left(9x + 1\right)$ $= \left( -9x \cdot 9x \right) + \left( -9x \cdot 1 \right) + \left( -6 \cdot 9x \right) + \left( -6 \cdot 1 \right)$ $= -81x^2 + \left( -9x \cdot 1 \right) + \left( -6 \cdot 9x \right) + \left( -6 \cdot 1 \right)$ $= -81x^2 + \left( -9x - 54x \right) + \left( -6 \cdot 1 \right)$ $= -81x^2 - 63x + \left( -6 \cdot 1 \right)$ $= -81x^2 - 63x - 6$